Stacker
You are basically correct.
When an aircraft engages a Barrier firstly a shear pin or similar will shear allowing the top of the net to break away from the stanchion. Tie downs (securing the net to the runway) will also break away from the bottom of the net. The bottom of the net is attached by cables or tapes to the Energy Absorbing Unit (EAU) which will pay out gradually bringing the Aircraft to a halt. As can be seen there is still tension on the net which is what has stood the Hawk on it's tail. Once the brake pressure in the EAU has been released as can be seen in the later pictures the Aircraft is back on 3 wheels. Looking at another picture it could also have used the maximum runout available (note proximity of fence and ditch) which will also have the same effect. I should add that when a Barrier Net or Arresting Cable is under tension like that you never ever go inside the Vee that is formed by the cables and the Aircraft as if something gives way you stand a good chance of losing your head!